Various different formats of vacuum cleaners are known in the art. These include upright vacuum cleaners, canister vacuum cleaners, stick vacuum cleaners and central vacuum systems. Typically, a vacuum cleaner uses a combination of mechanical action (e.g. a rotating brush) and suction to entrain material in a dirty air stream that enters the vacuum cleaner. The dirty air stream is treated in one or more steps as the dirty air passes through the vacuum cleaner. Typically, vacuum cleaners use cyclonic separation and/or physical filter members (e.g. filters) to remove entrained material from a dirty air stream that enters the vacuum cleaner.
An advantage of cyclone separators when used to remove entrained material from a dirty air stream that enters a vacuum cleaner is that the vacuum cleaner has a generally constant level of performance as the cyclone separator collects dirt and other entrained material. Prior to the use of cyclone separators, vacuum cleaners typically used filter bags to clean a dirty air stream. The filter bag had a dirty air inlet. The motor and fan assembly of the vacuum cleaner caused the dirty air stream to pass through the dirty air inlet of the filter bag and to then pass out of the air permeable walls of the filter bag thereby filtering the air. As the filter bag was used, the pores in the walls of the filter bag became blocked thereby reducing the airflow through the vacuum cleaner and reducing the cleaning efficiency of the vacuum cleaner.
An advantage of filter bags is that the bag does not have to be emptied by a user. Instead, the bag is thrown away and a new bag installed. However, when a used filter bag is removed from a vacuum cleaner and moved to a garbage can of the like, dirt escapes from the bag. While cyclone separators enable the construction of vacuum cleaners that have constant cleaning performance, a cyclone separator must be emptied by a consumer when the cyclone separator is full.
In the past, it has been taught to use a liner in a cyclone separator of a vacuum cleaner to simplify the emptying of the cyclone separator. See U.S. Pat. No. 5,090,976 (Dyson). However, the use of the liner still requires the user to open the cyclone separator and manipulate the liner for disposal, thus resulting in the release of collected dirt into the air.